Step 1: Understanding the Metric System.
In the metric system, 1 metre is equal to 10 decimetres. This is a basic conversion between the units in the metric system.
Step 2: Verifying the Options.
- Option (1): 1 metre equals 10 decimetres, making this the correct answer.
- Option (2): 20 decimetres would be 2 metres, not 1.
- Option (3): 30 decimetres is much too large for 1 metre.
- Option (4): 40 decimetres is also incorrect.
Conclusion:
Therefore, the correct answer is (1) 10.